It really does depend on your body length and your height... sit in a chair... with arms that are adjustable.. raise the arms until they reach your arms.. you should bend your arms at the elbows and the arms of the chair should come up to them..that's the perfect fit...you should not lean on either side to reach the arm rests of your chair... then with your arms and hand straight out that's where the bed of your machine should be... just like a key pad for your computer. That's why some computer tables work so well if the drawer for the keypad will hold your machine... for most of us putting the machine down in the table works . But for taller quilters this does not work.
Judy